Despite learning so much in our first years of life, most adults can’t recall specific memories from infancy. Scientists long assumed this was because the hippocampus, the brain’s memory center, was still developing and incapable of encoding memories. But new research from Yale University challenges belief on infant memory.
A study published in Science reveals that babies as young as four months old can form episodic memories. These are the kind of memories we use to recall specific events. This discovery raises an intriguing question. Infants are capable of memory encoding, so why do those memories fade as we grow?
INFANT BRAINS CAN ENCODE MEMORIES, STUDY SHOWS
The Yale research team, led by Nick Turk-Browne and Tristan Yates, tested infant memory using a simple but clever method. They showed 26 infants (aged 4 months to 2 years) images of faces. They also showed them objects and scenes. The researchers monitored their brain activity using functional magnetic resonance imaging (fMRI).
After a series of new images, the infants were shown an image they had already seen alongside a new one. If the babies stared longer at the previously seen image, it suggested recognition.
Their findings revealed a striking connection:
- Greater hippocampal activity during the first viewing of an image correlated with stronger recognition later on.
- The posterior hippocampus, the same region responsible for episodic memory in adults, was most active in older infants (12+ months).
- Memory strength increased with age, suggesting the hippocampus develops its ability to encode episodic memories over time.
These results confirm that memories can be stored during infancy. Nonetheless, if babies can encode memories, why do they later become inaccessible?
INFANTILE AMNESIA: A RETRIEVAL PROBLEM, NOT A STORAGE ISSUE?
The inability to recall early-life memories is known as infantile amnesia. Until now, researchers believed these memories were never stored properly due to hippocampal immaturity. But the new study suggests another possibility: the memories are there—we just can’t retrieve them.
Turk-Browne and his team are now exploring how long these memories persist. Early findings show that infants may retain some memories into their preschool years before they begin to fade.
This aligns with recent animal studies. They suggest that infantile amnesia is not due to memory loss. Instead, it is a failure in retrieval. The memories may remain in the brain, buried beneath newer experiences, perhaps even lasting into adulthood but remaining inaccessible.
ROLE OF STATISTICAL LEARNING IN INFANT DEVELOPMENT
Interestingly, infants rely on another type of memory before episodic memory fully develops: statistical learning. This allows them to recognize patterns and structures in their environment—critical for understanding:
- Language (associating words with meaning)
- Visual recognition (identifying faces and objects)
- Social behavior (predicting interactions)
Unlike episodic memory, which is stored in the posterior hippocampus, statistical learning occurs in the anterior hippocampus. It develops much earlier. This suggests that infants prioritize learning patterns first. They encode specific experiences afterwards. This may explain why personal memories are less likely to persist.
WHERE DO INFANT MEMORIES GO?
There are three main theories about what happens to early-life memories:
- They never transfer to long-term storage.
- Infants encode memories, but they aren’t reinforced enough to last.
- They persist but are buried beneath new memories.
- Early experiences may still exist, but as the brain develops, it reorganizes and prioritizes new information, making access difficult.
- They remain in a hidden form, possibly retrievable.
- Turk-Browne’s team is investigating whether certain cues—like home videos of infancy—could help recover lost memories.
If early memories are still present but inaccessible, could future research unlock them? The idea sounds like science fiction, but researchers are already exploring this possibility.
FUTURE RESEARCH: UNLOCKING THE SECRETS OF INFANT MEMORY
The Yale study provides groundbreaking evidence that infants encode memories earlier than previously thought. Moving forward, researchers will:
- Track hippocampal memory durability from infancy through childhood.
- Test if early memories can be retrieved using specific cues.
- Explore links between infant memory and adult cognition, potentially uncovering whether lost memories influence later brain function.
If scientists find a way to access early memories, it could revolutionize our understanding of memory storage, retrieval, and even neurological disorders like Alzheimer’s.
A BRAIN FULL OF FORGOTTEN STORIES?
If memories from our infancy are still hidden within our brains, could they ever be reawakened? While we may never recall our first steps or first words, science is beginning to unravel the mystery of infantile amnesia.
Perhaps the memories of our earliest years never truly disappear—they may just be waiting for the right key to unlock them.
